(a) Field of the Invention
The present invention relates to a mounting bolt for a sub-frame. More particularly, the present invention relates to a mounting bolt for a sub-frame that uses a joining plate of a steel material to be welded to a mounting bracket through one welding process.
(b) Description of the Related Art
Generally, a sub-frame is assembled to a lower portion of a front side member in a monocoque vehicle body structure.
The sub-frame supports an engine and a transmission, and induces the engine and the transmission to be dropped such that the engine or the transmission does not push into an interior room through a dash panel to secure safety of a passenger.
FIG. 1 is a perspective view for describing a general sub-frame assembled to a lower portion of a front side member for a vehicle, and FIG. 2 is a perspective view of a mounting unit for a sub-frame according to a conventional art.
Referring to FIG. 1, both sides of a front and a rear of the sub-frame 101 are assembled by a mounting unit 100 for a frame (hereinafter, a mounting unit) that is configured at a lower portion of both sides of a front side member 103.
Referring to FIG. 2, the mounting unit 100 includes a mounting bolt 110 that is fixed to both sides of a front and a rear of the front side member 103 through a mounting bracket 105, and both sides of a front and a rear of the sub-frame 101 are assembled to the mounting bolt 110.
That is, the mounting bracket 105 is joined to a lower portion of both sides of a front and a rear of the front side member 103.
Also, the mounting bolt 110 is joined by CO2 welding or projection welding in a condition that it is inserted into a through-hole 107 formed on the mounting bracket 105.
Here, the mounting bolt 110 is integrally formed by cold forging or hot forging, and is welded in a condition that it is supported to a circumference of the through-hole 107 of the mounting bracket 105 by a flange portion 111 that is formed along one side circumference.
However, the mounting bolt 110 that is configured as described above has a drawback that the weight is unnecessarily heavy, because it is integrally formed by cold forging or hot forging, and this is a cause that increases cost.
The Description of the Related Art is made to help understanding the background of the present invention, and may include matters out of the related art known to those skilled in the art.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.